Liquid crystal display devices have been improved in terms of display characteristics, and are now used for TV receivers and the like more and more widely. The viewing angle characteristics of the liquid crystal display devices have been improved but are desired to be further improved. Especially, the viewing angle characteristics of liquid crystal display devices using a vertical alignment type liquid crystal layer (also referred to as the “VA-mode liquid crystal display devices”) are strongly desired to be improved.
VA-mode liquid crystal display devices currently used for large display devices of TVs and the like adopt a multi-domain structure in which a plurality of liquid crystal domains are formed in one pixel in order to improve the viewing angle characteristics. A mainly used method for forming the multi-domain structure is an MVA mode. The MVA mode is disclosed in, for example, Patent Document 1.
According to the MVA mode, a pair of substrates facing each other with a vertical alignment type liquid crystal layer interposed therebetween each include an alignment regulation structure on a surface thereof on the liquid crystal layer side. Owing to such alignment regulation structures, a plurality of domains having different alignment directions (tilt directions) of liquid crystal molecules (typically, there are four types of alignment directions) are formed in each pixel area. As the alignment regulation structures, slits (openings) or ribs (protrusion structures) provided in or on electrodes are used, and an alignment regulation force is exerted from both sides of the liquid crystal layer.
However, in the case where the slits or ribs are used, unlike in the case where the pretilt directions are defined by alignment films used in the conventional TN mode, the alignment regulation force on the liquid crystal molecules is nonuniform in the pixel area because the slits and ribs are linear. This causes a problem that, for example, there occurs a response speed distribution. There is another problem that since the light transmittance of an area where the slits or ribs are provided is lowered, the display luminance is decreased.